ILSpy/SharpTreeView/ExtensionMethods.cs

// Copyright (c) AlphaSierraPapa for the SharpDevelop Team (for details please see \doc\copyright.txt)
// This code is distributed under the GNU LGPL (for details please see \doc\license.txt)

using System.Collections.Generic;
using System.Linq;
using System.Windows.Media;
using System.Windows;
using System.Collections;

namespace ICSharpCode.TreeView
{
	static class ExtensionMethods
	{
		public static T FindAncestor<T>(this DependencyObject d) where T : class
		{
			return AncestorsAndSelf(d).OfType<T>().FirstOrDefault();
		}

		public static IEnumerable<DependencyObject> AncestorsAndSelf(this DependencyObject d)
		{
			while (d != null) {
				yield return d;
				d = VisualTreeHelper.GetParent(d);
			}
		}

		public static void AddOnce(this IList list, object item)
		{
			if (!list.Contains(item)) {
				list.Add(item);
			}
		}
	}
}